Most motors have screw holes on the front to mount the motor to a bracket or device. For whatever reason, the extremely-heavily-geared motor (2050:1) that I selected for a polarizer test apparatus lacks motor-mounting holes. This is not the first time I’ve run into small DC motors that are missing obvious ways to secure them.
Drilling holes into a tiny gearbox is a dicey prospect, since you can’t see the locations of the delicate gears. Instead of risking damage to an expensive motor, it’s better to figure out a different method of mounting it.
Two similar miniature electric motors. The motor on the right doesn’t have any mounting holes.
Previously, I’ve tried mounting a motor inside of a solid block of material, with the motor held in place with the tip of a screw. Unfortunately, the screw dented the thin motor case, which pressed into the gears, thereby ruining the motor. (For more details, see the repairs to the Chicago Line-Following Robot.)
Electric motor damaged by attempting to secure it with setscrews.
Instead of using the tip of a screw, a better choice is to turn the block itself into a large clamp. This spreads the holding force across a much larger area.
A clamping motor mounting block provides plenty of locations for adding attachments. Notice the screws are on the side. They don’t make contact with the motor.
One advantage of a motor mounting block is that it provides a lot of faces and places to attach it to the robot or project. Some disadvantages are that a mounting block takes up space and adds weight.
This clamp-based mounting block is suited for a variety of robots, test equipment, and mechanical contraptions. It’s surprisingly easy to make for small motors.
Let’s see how...